Question

How to print only one time the statement if a few wrong input is key in:
Eg:
if key in kkk, only will print one statement instead of the example below.
sample output:
Do you wish to try again (Type Y to continue Q to quit:kkk
Error: Invalid choice

Do you wish to try again (Type Y to continue Q to quit:Error: Invalid choice

Do you wish to try again (Type Y to continue Q to quit:

//Code
valid=0;
        while (valid==0)
        {
            printf("
Do you wish to try again (Type Y to continue Q to quit:");   // print statement request for input
            scanf(" %c", &choice);                                                 // get user input
            choice = toupper(choice);
            if((choice == 'Y') || (choice == 'Q')) valid= 1;
            else printf("Error: Invalid choice
");                                // statement
        }

Accepted Answer

Answer on Question #62455 , Programming & Computer Science / C

How to print only one time the statement if a few wrong input is key in:

Eg:

if key in kkk, only will print one statement instead of the example below.

sample output:

Do you wish to try again (Type Y to continue Q to quit:kkk

Error: Invalid choice

Do you wish to try again (Type Y to continue Q to quit:Error: Invalid choice

Do you wish to try again (Type Y to continue Q to quit:

//Code

valid=0;

while (valid==0)

{

printf("\nDo you wish to try again (Type Y to continue Q to quit:"); // print statement request for input

scanf("%c", &choice); // get user input

choice = toupper(choice);

if((choice == 'Y') || (choice == 'Q')) valid= 1;

else printf("Error: Invalid choice\n"); // statement

}

Answer:

If you want to print only one time the statement if a few wrong input is entered, you have to clear stdin stream (read all symbols from it).

First method is to use fflush(stdin);

Second method is to read all symbols from the stdin stream using loop^

do {

choice = getchar();

} while (choice != '\n' && choice != EOF);

So you have to change your code like below:

Method 1

valid=0;
while (valid==0)
{
printf("\nDo you wish to try again (Type Y to continue Q to quit:"); /* print statement request for input */
scanf("%c", &choice); /* get user input */
choice = toupper(choice);
if((choice == 'Y') || (choice == 'Q'))
valid = 1;
else
{
printf("Error: Invalid choice\n"); /* statement */
fflush(stdin);
}
}

Method 2

valid=0;
while (valid==0)
{
printf("\nDo you wish to try again (Type Y to continue Q to quit:"); /* print statement request for input */
scanf("%c", &choice); /* get user input */
choice = toupper(choice);
if((choice == 'Y') || (choice == 'Q'))
valid = 1;
else
{
printf("Error: Invalid choice\n"); /* statement */
do {
choice = getchar();
} while (choice != '\n' && choice != EOF);
}
}

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Question #62455

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